A known parking assist apparatus calculates a traveling locus of a vehicle to a target parking position and guides the vehicle along the calculated traveling locus. Such a parking assist apparatus is disclosed in Japanese Patent Laid-Open Publication No. H10-264839. According to the disclosed parking assist apparatus, a deviation amount of a present vehicle position from the calculated traveling locus is calculated while the vehicle is guided to the target parking position. When the deviation amount reaches or exceeds a predetermined value, the traveling locus to the target parking position is recalculated to thereby specify a new traveling locus required for a movement of the vehicle. Therefore, the vehicle may be guided along a newly calculated traveling locus each time the vehicle is deviated from the traveling locus to the target parking position according to the disclosed parking assist apparatus.
According to the disclosed parking apparatus, the vehicle is appropriately guided to the target parking position by calculating the new traveling locus in case that the vehicle is slightly deviated from the initially calculated traveling locus due to a small obstacle such as an inclination of a road and a stone, a disturbance such as a change of a wheel radius caused by a change of a load mounted on the vehicle, and the like. However, if an error of a system itself of the parking assist apparatus occurs, the vehicle cannot be ultimately guided to the target parking position even though the new traveling locus is calculated. As a result, the vehicle cannot be parked in the target parking position.
When the new traveling locus is repeatedly calculated each time the deviation of the present vehicle position from the initially calculated traveling locus is detected to thereby guide the vehicle to the target parking position, the vehicle may move in an unexpected manner due to the continuation of the parking assist control.
Thus, a need exists for a parking assist apparatus that can stop a parking assist control immediately when a system error occurs.